To repair an existing aging conduit such as a water supply or sewer pipe, a pipe for agricultural water, or a gas pipe, there have been conventionally known methods as follows: a tubular lining material containing a liquid curable resin with reinforced fibers is installed on an inner surface of the existing conduit, and then the liquid curable resin is cured, thereby to construct, in the conduit, a robust lining structure including a fiber reinforced resin.
In a method described in Patent Literature 1, a base material sheet is used for a lining material. The base material sheet is formed of non-woven fabrics of organic fibers and woven fabrics made of glass yarns, in which non-woven and woven fabrics are laid on one another and jointed by needlepunching, and the base material sheet is impregnated with a liquid thermosetting resin. The base material sheet is rolled into a tubular form, and overlapping both ends of the base material sheet in its circumferential direction, that is, the overlapping both circumferential ends (an overlapping portion) are jointed to each other by a hot melt adhesive, to form the lining material. An outer surface of the lining material is composed of an impermeable tubular woven fabric. In the method described in Patent Literature 1, first, the tubular lining material is installed in a conduit, while being inverted so as to be inside out by applying compressed air (installation step). Then, a heating medium such as heated air or steam is supplied to the inside of the lining material, and thereby the lining material is pressurized from the inside thereof while being heated, to expand the diameter of the lining material (diameter expansion step). That cures the liquid thermosetting resin included in the lining material which is in close contact with the conduit, to form the robust lining structure on the inner surface of the conduit.